These chemicals were discarded by looters, who tipped them out, unaware of their value or toxicity, in order to obtain the drums in which they had been kept; presumably the drums in question have subsequently been used to store water or other things.
Esos productos químicos fueron desechados por los ladrones, que los abandonaron, sin ser conscientes de su valor ni de su toxicidad, para quedarse con los bidones que los contenían; cabe suponer que los bidones en cuestión se han utilizado para almacenar agua y otras cosas.